JP4528336B2 - How to read a test strip - Google Patents

Description

  It is often desirable to quantitatively evaluate the intensity of the red line color on the white test strip.

For example, U.S. Patent Application Publication No. 2004/0131238 describes the color intensity of a colored line on a white test strip by analyzing one or more individual scan lines obtained along the length of the test strip. If it is desirable to use data from multiple scan lines, the sample length must be perfectly parallel to the scan direction, otherwise data analysis is very It becomes complicated.
US Patent Application Publication No. 2004/0131238

  A method of analyzing the intensity of the red line color on a white test strip, with relatively simple calculations and insensitive to changes in the angle between the long axis of the test strip and the scan direction It is desirable to do.

In one aspect of the invention, a method for identifying the intensity of a red line color on a white test strip comprising:
(A) attaching the white test strip to a card that is larger and darker than the white test strip;
(B) scanning the card with the attached white test strip;
(C) creating a digital image of the card, wherein each pixel in the digital image has a red value, a green value, and a blue value;
(D) A method is provided that includes calculating a color intensity for each red line on the white test strip using the digital image.

  As used herein, a strip is a relatively thin, elongated object. In some embodiments, suitable strips have a thickness of 1 mm or less; or 0.5 mm or less. The ratio of test strip length to width is 1.5 or greater. Test strips are recognized as white in the present invention if most observers judge that the color is white; test strips are those that are, for example, cream, eggshell, or If it is any white shade, including any other shade that would normally be recognized as white, it is suitably white.

  The direction parallel to the length of the strip is identified herein as the “vertical” direction, and the direction parallel to the short dimension of the strip is identified herein as the “horizontal” direction. That is, the vertical size of the strip is the length of the strip, and the horizontal size of the strip is the width of the strip. The end of the strip running in the vertical direction is identified herein as the vertical end, and the other end is identified herein as the horizontal end.

  A strip is recognized herein as a pre-test strip if it contains one or more test lines. The test line is an area containing the assay substance. The test line extends to a region extending horizontally from one vertical end of the pre-test strip to the other vertical end. The test line has a width that is much smaller than the length of the pre-test strip (ie, the size of the test line measured in the vertical direction). In some embodiments, the ratio of test line width to pre-test strip length is 0.2 or less; or 0.1 or less; or 0.03 or less; or 0.01 or less.

  An assay substance is a substance sensitive to a specific target substance. That is, the assay substance contained in or on the pre-test strip is not visible, but the assay substance can form a colored substance when contacted with a particular target substance. That is, the pre-test strip initially appears white throughout, and the test line appears to have color after the pre-test strip has been contacted with a particular target material. In some embodiments, the one or more test lines appear red. In some embodiments, each test line that appears to have color appears red. The pre-test strip can have multiple test lines, and each test line can be sensitive to a different target material. Each test line is assumed to be separated from all other test lines on the pre-test strip. In some embodiments, the ratio of the distance between two test lines to the average width of the test lines on the pre-test strip is 1 or more, or 2 or more, or 5 or more.

  The pre-test strip can be contacted in some way with one or more target substances. For example, in some embodiments, a solution that can contain one or more target substances can be identified.

  After the pre-test strip is contacted with the solution, the strip is identified herein as a test strip. It is assumed that the test line on the test strip appears white if the solution did not contain the target substance to which the test line was sensitive. If the solution contained a target substance to which the test line was sensitive, the test line on the test strip appears colored and the higher the intensity observed on the test line, the higher the intensity of the color observed on the test line. It is further assumed that the concentration in the solution of the target substance that was sensitive to was increased.

  The pre-test strip can be made of any material. Some suitable pre-test strips are made from a porous material (eg, paper or cardboard) or a non-porous material, eg, a polymer film.

  In some embodiments, the width of the pre-test strip is 2 mm or more, or 5 mm or more, or 10 mm or more. Independently, in some embodiments, the length of the pre-test strip is 100 mm or less, or 75 mm or less, or 50 mm or less.

  It is envisaged to use a solution of interest that may or may not contain a particular target substance (as used herein, “analyte” is synonymous with the target substance). If so, it is desirable to determine what concentration of analyte is present in the solution of interest.

  One way to determine the concentration of an analyte in a solution of interest is to first add one or more additional reagents to the solution of interest and optionally dilute the solution of interest. In some embodiments, such addition of additional reagents results in a test solution containing the reference material and the subject material. In some of such embodiments (referred to herein as “RS” embodiments), it is envisaged that the resulting solution is contacted with a particular type of pre-test strip. This particular pre-test strip has at least two test lines, one of which (reference line) is sensitive to the reference substance and one of which (subject line) is sensitive to the target substance. is there.

  In an RS embodiment, when a solution is contacted with such a pre-test strip to obtain a test strip, the baseline is colored if the reference material is present in the solution, and the concentration of the reference material present in the solution is The higher the color, the greater the color intensity of the reference line. Similarly, the target line is colored when the target substance is present in the solution, and the higher the concentration of the target substance in the solution, the greater the intensity of the target line color.

  In the RS embodiment, the analyte, additional reagents, optional dilutions, and pre-test strips are linear with the concentration of the analyte in the solution in which the ratio of the color intensity of the subject line to the intensity of the baseline color is of interest. It will be appreciated that a choice can be made to have a social relationship.

  For example, in some embodiments, it can interact with an analyte to form a chemical complex, or can react with an analyte to form a reaction product, or can bind to an analyte, or any of its Reference materials that can be combined can be used. In such an embodiment, the target substance is a chemical complex or a reaction product, while the reference substance is an unreacted or unreacted additional reagent.

  In some embodiments (referred to herein as “chromatographic” embodiments), a solution containing the analyte and optionally additional reagents (single or multiple) in a container (eg, a vial) And to a slight depth compared to the length of the pre-test strip. One end of the pre-test strip can then be placed in the container in such a way as to hold the pre-test strip upright or nearly upright. In such an embodiment, it is envisioned that each test line on the pre-test strip is located in the pre-test strip above the liquid solution surface at the bottom of the container. A portion of the solution may be a chromatographic process, e.g., capillary action, thin layer chromatography, paper chromatography, other chromatographic processes, or the like, as the solution moves from the bottom of the pre-test strip to the top of the pre-test strip. When moving in combination, it is likely that they will come into contact with most or all of the pre-test strips. As the solution comes into contact with a particular test line, it is envisaged that if the solution contains a substance of interest to which the test line is sensitive, the test line will form a colored material.

  In some chromatographic embodiments where the solution contains a reference substance and a target substance, the test line that is sensitive to the reference substance is configured to be below the test line that is sensitive to the target substance. A pre-test strip is used. In such an embodiment, the solution contacts a test line that is sensitive to the reference substance before contacting the test line that is sensitive to the target substance. Such an embodiment is referred to herein as an “LRC” embodiment.

  In some embodiments, the analyte in the present invention is a polymer. As used herein, FW Billmeyer, JR. As defined in Textbook of Polymer Science, 2nd edition, 1971, is a relatively large molecule composed of reaction products of smaller chemical repeat units. Usually, the polymer has 11 or more repeating units. The polymer may have a structure that is linear, branched, star, looped, hyperbranched, cross-linked, or combinations thereof; the polymer may have a single type of repeating unit. Well (homopolymer) or may have more than one type of repeating unit (copolymer). As used herein, a “copolymer” is a polymer that contains two or more different types of repeat units. Copolymers can have various types of repeating units arranged in random, sequence, block, or other sequences, or any mixture or combination thereof. Chemicals that react with each other to form a repeating unit of the polymer are identified herein as “monomers”, and polymers are herein referred to as “polymerized units” of monomers that react to form repeating units. Said to be composed. The chemical reaction (single or multiple) that the monomer reacts into a polymerized unit of polymer is referred to herein as “polymerize” or “polymerization”.

  Polymer molecular weight can be measured by standard methods such as, for example, size exclusion chromatography or intrinsic viscosity. Generally, the polymer has a weight average molecular weight (Mw) of 500 or greater.

  Some polymers suitable as analytes in the present invention have a detectable end selected from a chain transfer agent, an initiator (or fragment thereof), a group attached to the chain transfer agent, or another functional group. Such polymers are recognized herein as “DT” polymers. DT polymers are effectively described as comprising a body polymer and one or more covalently attached detectable ends. In some embodiments, such polymers are also water soluble.

  Some polymers suitable as the body polymer are, for example, polymers or copolymers of carboxylic acids, in particular acrylate polymers and derivatives thereof. Some suitable acrylate polymers are, for example, ethylenically unsaturated monocarboxylic acids containing 3-5 carbon atoms per molecule, and ethylenically unsaturated monomers containing 4-8 carbon atoms per monomer molecule. Polymers and copolymers made from monomers of saturated dicarboxylic acids, their alkali metal and ammonium salts, and cis dicarboxylic acid anhydrides are included. Examples of monocarboxylic acids include, but are not limited to: acrylic acid, methacrylic acid, vinyl acetic acid, crotonic acid, and acryloxypropionic acid. Of these, acrylic acid and methacrylic acid are known to be suitable, for example. Examples of suitable dicarboxylic acid monomers include, but are not limited to: maleic acid, itaconic acid, mesaconic acid, fumaric acid, citraconic acid, tetrahydrophthalic acid, tetrahydrophthalic anhydride, and maleic anhydride. Of the dicarboxylic acid monomers, maleic anhydride is known to be suitable, for example.

  Polymers suitable as the body polymer may further be composed of up to 70 weight percent (wt%) monoethylenically unsaturated monomers free of acid, so long as the polymer remains water soluble. Such other monomers include, but are not limited to: alkyl esters of acrylic acid or methacrylic acid, such as methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, and isobutyl methacrylate; acrylic acid or Hydroxyalkyl esters of methacrylic acid, such as hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate, and hydroxypropyl methacrylate; other types of acrylates or methacrylates, such as 2-sulfoethyl (meth) acrylate, 3-sulfopropyl (meta ) Acrylate, 2-sulfatoethyl (meth) acrylate, dimethylaminoethyl acrylate And phosphoethyl methacrylates; acrylamides and alkyl-substituted acrylamides such as methacrylamide, t-butylacrylamide, Nt-butyl-acrylamide, N-methylacrylamide, N, N-dimethylacrylamide, and 3-N, N- Acrylonitriles such as methacrylonitrile; allyl alcohol; allyl sulfonic acid; allyl phosphonic acid; vinyl phosphonic acid; 2-vinyl pyridene; 4-vinyl pyridene; N-acrylomorpholine; acrolein; ethylene glycol diacrylate; trimethylolpropane triacrylate; diallyl phthalate; vinyl acetate; Vinyl sulfonic acid; p-styrene sulfonic acid, and 2-acrylamido-2-methylpropane sulfonic acid; methallyl sulfonate and 1-allyloxy-2-hydroxypropyl sulfonate (COPS.RTM.); Acrylamide glycolic acid; and if appropriate For example, the above salts are included.

  In some embodiments, the body polymer is polyacrylic acid (PAA), polymaleic acid, or a copolymer of acrylic acid and one or more additional monomers.

  Independently, some body polymers have a number average molecular weight (Mn) of 500 or greater, or 1000 or greater, or 2000 or greater. Independently, some body polymers have a number average molecular weight of 1 million or less; or 500000 or less; or 100000 or less; or 50000 or less, or 25000 or less.

  Also contemplated are embodiments in which a body polymer having a weight average molecular weight of 1,000,000 to 30,000,000 is used.

  Any chain transfer agent useful for controlling the molecular weight of the polymer composition can be used as a detectable terminus in the present invention. Such chain transfer agents include, but are not limited to: mercaptans, phosphinates, phosphonates, sulfinic acids (eg, phenylsulfinic acid and p-toluenesulfinic acid), and amine-thiols. . Suitable phosphinates are those disclosed as compounds of formula I (col. 1) in US Pat. No. 5,294,371 (Crubley et al.) And in US Pat. No. 5,376,731 (Kerr et al.). Suitable amine-thiols, including those disclosed as compounds of formula III (col. 4), include those of the type disclosed in US Pat. No. 5,298,585 (McCallum et al.). . In some embodiments, it is preferred to use cysteine (CYS), aminoethanethiol (AET), or phenylphosphinic acid (PPA) as the chain transfer agent.

  Any initiator or initiator fragment useful in initiating free radical addition polymerization can be used as a detectable terminus in the present invention. Such initiators or initiator fragments include, but are not limited to: peroxyesters such as t-butyl-perbenzoate and t-amylperoxybenzoate; dialkyl peroxides such as dicumyl peroxide; diacyl peroxides such as benzoyl peroxide. Hydroperoxides such as cumene hydroperoxide; azo compounds such as 2-phenylazo-4-methoxy-2,4-dimethyl-valeronitrile, 2,2′-azobis-2-methyl-N-phenylpropionamidine dihydrochloride Salt, 2,2′-azobis-2 (N- (4-chlorophenyl) -2-methylpropionamidine) dihydrochloride, 2,2′-azobis- (2- (5-methyl-2-imidazoline-2- Il) propane) dihydrochloride, oh Beauty 2,2'-azobis (2- (2-imidazolin-2-yl) propane), and the dihydrochloride salt.

  In embodiments where the detectable terminus is a group attached to a chain transfer agent, the optimal chain transfer agent is an amine-thiol, particularly CYS or AET. Groups that can be attached to such chain transfer agents are groups that react specifically with the desired group but do not react with other parts of the polymer. Where the chain transfer agent contains pendant amines, it is preferred to attach amine reactive groups to them as detectable termini. Suitable amine-reactive groups include, but are not limited to: 1- (dimethylamino) -5-naphthalenesulfonic acid and its halide (dansyl “dansyl”); 4-dimethylaminoazobenzene-4-sulfonic acid and its halide (Dabsyl “dabsyl”); 2,4,6-trinitro-benzenesulfonic acid and its salts (TNT); 3-benzoylquinoline-2-carboxaldehyde; 3- (2-furoyl) quinoline-2-carboxaldehyde; 2 , 4-dinitrofluorobenzene (Sanger reagent); and ninhydrin. In some embodiments, suitable groups include: daisyl, dabsyl, and TNT.

Some commercially available examples of suitable polymers with detectable ends are OPTIDOSE ^™ 1000 (sodium salt of polycarboxylate), OPTIDOSE ^™ 2000 (modified polycarboxylate), OPTIDOSE ^{™ )} 3100 (carboxylate, sulfonate, and terpolymers of nonionic monomers), and OPTIDOSE ^(TM) 4210 (polymaleic acid) (available from Rohm and Haas Company).

  In some embodiments, a solution containing a DT polymer and an additional polymer is used; the additional polymer is similar to or the same as the body polymer of the DT polymer, and the additional DT polymer in the solution The weight ratio to the polymer is known. It is envisioned that the present invention can be used to determine the concentration of DT polymer in solution so that the amount of additional polymer in solution can be readily determined.

  In some RS embodiments where the analyte contains a DT polymer, a reference material containing an antibody is used. In embodiments where the reference material contains an antibody, the antibody may optionally be conjugated to a marker. It is envisioned that the antibody itself or an antibody conjugated to a marker can form a complex with the detectable end of the DT polymer. It is further envisaged to use a molar excess of antibody or antibody bound to the marker in comparison to the detectable end site of the DT polymer; thus, the solution was complexed with (1) the antibody or antibody bound to the marker. It has a mixture of DT polymer and (2) an antibody or an antibody conjugated to a marker that is “free” (ie, not complexed with the DT polymer).

  In such embodiments using an antibody conjugated to a DT polymer and an antibody or marker, the first test line is a reference test line and can trap free antibody or antibody bound to the marker, It is envisioned to contain an assay substance (reference assay substance) that is unable to trap the DT polymer complexed with the antibody bound to the marker. Such reference assay substances can be based, for example, on immunoassay techniques. It is further envisioned that the second test line is the target test line and contains the target assay that can trap all antibodies bound to the marker, whether free or complexed. Is done. Such subject assay substances may be based, for example, on immunoassay techniques. It is envisioned that the reference assay substance and the subject assay substance are different substances, even in embodiments both based on immunoassay technology.

  In the practice of the present invention, the test strip is attached to a darker card that is larger than the test strip. Some suitable cards are, for example, rectangular and larger than the test strip. As used herein, “darker” means that the card is some color that is easily distinguished from white. In some embodiments, the color of the card has a significantly higher blue value than the color of the pre-test strip. Suitable cards may be flexible or rigid enough to be self-supporting when holding one end. A suitable card can be, for example, 3 mm thick or less, or 2 mm thick or less, or 1 mm thick or less. Independently, some suitable cards may be made from cardboard, for example. Independently, in some embodiments, cards with a ratio of card width to test strip width of 1.5 or greater, or 3 or greater, or 5 or greater are used. Independently, in some embodiments, a card is used in which the ratio of card length to test strip length is 1.1 or greater, or 1.2 or greater. Independently, cards with a ratio of length to width of 1.2 or more, or 1.5 or more, or 2 or more are used.

  It is envisaged that the flat surface of the test strip is attached to the flat surface of the card so that the colored line (s) on the test strip can be seen. It is envisioned that the length of the test strip is parallel or nearly parallel to the length of the card and the test strip is centered or approximately centered in the horizontal direction on the card. Any type of fastening system that does not significantly deform or discolor the test strip can be used to attach the test strip to the card, such as tape, glue, or other adhesive. If tape is used, transparent tape is suitable.

  In the practice of the present invention, the card with the test strip attached is optionally scanned to create a digital image of the card with the test strip attached. A digital image assigns a red value, a green value, and a blue value to each pixel.

  Any scanner and accompanying electronic circuitry (including software) that is capable of generating such a digital image is suitable. In some embodiments, a portable scanner designed to scan business cards is used.

  In some embodiments, the scanner is adjusted for the pre-test strip as follows. Scan the pre-test strip (which appears white throughout), calculate the average response over the entire area of the pre-test strip for the red, green, and blue detectors respectively, and set the average response for each detector to a value of 256 To do. In embodiments where such adjustments are made, such adjustments are made periodically over time, and the white area of each pre-test strip may produce red, green, and blue values close to 256 or 256, respectively. is assumed.

  In the practice of the present invention, the digital image is used to calculate the color intensity of each colored line on the test strip.

  The practice of the present invention is particularly useful when each colored line on the test strip is red.

  In some embodiments, images (referred to herein as “locator” images) are printed on the pre-test strip and these images remain visible after the pre-test strip becomes the test strip. Such an image is a known distance from each test line and assists in the process of finding the test line in the digital image of the card with the test strip attached. Independently, in some embodiments, one or more guide marks can be formed on the card prior to applying the test strip to assist in positioning the test strip on the card.

  In some embodiments, the process of calculating the color strength of the first red test line includes the following steps. First, the red line is identified. That is, the pixel portion corresponding to the red line is specified. For example, one way to identify the first red line is to look at each pixel in the vertical line starting from the bottom of the card. Pixels corresponding to vertical lines in a digital image may not form lines that are exactly parallel to the vertical edge of the test strip if the scanning direction is not exactly parallel to the vertical edge of the card. is assumed. Nevertheless, it is envisaged to examine the pixels in the line recorded as vertical in the digital image. For example, red and green values can be examined, and in the red line (only in the red line), the ratio of red value to green value (R / G ratio) is assumed to be greater than 1.2. Thus, a group of consecutive pixels in a vertical line having an R / G ratio greater than 1.2 identifies a red line. The central pixel in the group of consecutive pixels is characterized by a vertical coordinate (YR1) in the digital image. In the group of consecutive pixels, the two pixels furthest from the center pixel have YR1T and YR1B vertical coordinates. The vertical size of the first red line is therefore the absolute value of YR1T-YRTB in number of pixels.

  If desired, the location of the locator image can be easily identified, and the number of pixels in the vertical line between the locator image and the identified red line can be compared to a known distance between the locator image and the red line. Such a comparison can be used to assist in positioning the red line, if desired, or can serve as a specific confirmation of the red line.

  Next, pixels in the horizontal line (perpendicular to the scanning direction) are considered. If consecutive pixels far from the vertical scan line are considered, eventually the blue value spikes and the last pixel with a lower blue value is recognized as the vertical end of the test strip. The two vertical edges of the test strip can be determined in this way and they have the horizontal coordinates in the digital image of XR1L and XR1R. It is recognized that the horizontal center point of the first red line has a horizontal coordinate of XR1 = (1/2) × (XR1L + XR1R). The horizontal size of the first red line is an absolute value of XR1L-XR1R in terms of pixels.

  After the first red line is identified, the “first rectangle” corresponding to the first red line can then be identified. A rectangle is a group of pixels in a digital image that appears as a rectangle with sides perpendicular and parallel to the scanning direction if it marks (eg, by a distinct color) on the visible image of the digital image of the card. It is recognized. The first rectangle is just centered or nearly centered on the image of the test strip in the horizontal direction. The first rectangle has the center point of the pixel having the coordinates (XR1, YR1).

  The first rectangle has a horizontal size smaller than the horizontal size of the first red line. In some embodiments, the ratio of the horizontal size of the first rectangle to the horizontal size of the first red line is 0.9 or less, or 0.8 or less, or 0.7 or less. Independently, in some embodiments, the ratio of the horizontal size of the first rectangle to the horizontal size of the first red line is 0.3 or greater, or 0.5 or greater.

  The first rectangle has a vertical size larger than the vertical size of the first red line. In some embodiments, the ratio of the vertical size of the first rectangle to the vertical size of the first red line is 1.1 or higher, or 1.3 or higher, or 1.5 or higher. Independently, in some embodiments, the ratio of the vertical size of the first rectangle to the vertical size of the first red line is 5 or less, or 3 or less, or 2 or less.

  For each additional red line on the test strip, a corresponding rectangle can be found. For the nth red line, it is recognized that the corresponding nth rectangle is determined by the method described above for the first red line and the corresponding first rectangle. The positional relationship of the nth rectangle to the nth red line, the horizontal size of the nth rectangle to the horizontal size of the nth redline, and the vertical size of the nth redline of the vertical size of the nth rectangle All the relations to are the same as the relation to the first red line of the first rectangle.

  All identified rectangles are considered to have the same horizontal size as all other identified rectangles. In some embodiments, all identified rectangles have the same vertical size as other identified rectangles.

  In some embodiments, the color intensity of each red line is calculated by the following method. Color inversion, which applies a digital image of a card to a color inversion calculation, is a well-known calculation and is readily available in most image processing software programs. Within each identified rectangle, after color reversal calculation, pixels outside the red line have a green value close to 0; such pixels in the original test strip are white and therefore have a high green value. Have a red value, and a blue value; after color reversal, such pixels have a green value, a red value, and a blue value that are 0 or close to 0. Within each identified rectangle, the red line pixel has a significant red value before color inversion, which is converted to a green value after inversion.

  After color reversal, the sum of all green values of all pixels within each identified rectangle is calculated. Pixels outside the red line are considered to contribute little or no to such total. This total for the first rectangle is considered to be the intensity of the color of the first red line, and this total for the first red line is denoted herein as “CI1”. This sum for the second rectangle is considered to be the intensity of the color of the second red line, and this sum for the second red line is denoted herein as “CI2”. In general, this sum for the nth rectangle is considered to be the color strength of the nth red line, and this sum for the nth rectangle is denoted herein as “CIn”. .

  The method of color intensity calculation can be used, for example, on a test strip generated in the LRC embodiment. In such an embodiment, the first red line can be recognized as the test line closest to the liquid solution, and the second red line is a test line other than the first red line closest to the liquid solution. Can be acknowledged. In some of such embodiments, the first red line is a reference line and the second red line is a target line. In such an embodiment, there is a linear relationship between the concentration of the analyte in the solution (denoted herein as “CA”) and the ratio R of CI2 to CI1 (ie, R = CI2 / CI1). To do.

  The linear relationship between CA and R means the following in this specification. Various solutions (number N) are prepared (designated by the number “i” from 1 to N), each having a specific analyte concentration (designated CAi). Each solution is tested and analyzed as above, the value for R is calculated and listed as Ri. Taking the concentration value and the R value as a data pair (CAi, Ri), linear regression is performed to calculate a fitted straight line CA = m × R + b. If the well-known statistical R-square parameter of the fitted line is 0.8 or better, it is said herein that a linear relationship exists between CA and R.

  If a linear relationship exists between CA and R, this relationship is assumed to be valid over a finite range of CA values. If it is desired to analyze a solution with CA outside the range where the linear relationship is valid, the measurement should be such that the expected value of CA is within the range of CA values where the linear range is valid. It is further envisaged that the range of CA values for which the linear relationship is valid can be changed and done in different ways (eg by using different concentrations of reference material).

  In some embodiments, the linear relationship between CA and R is valid over concentrations from the lowest value (CAMIN) to the highest concentration value (CAMAX). In some embodiments, the ratio of CAMAX to CAMIN is 2 or higher; or 4 or higher; or 6 or higher.

  In some embodiments, the solution containing the analyte has an analyte concentration of 0.1 ppm or higher; or 0.2 ppm or higher; or 0.5 ppm or higher; or 1 ppm or higher, or 2 or higher, based on the weight of the solution. Independently, in some embodiments, the solution containing the analyte has an analyte concentration of 50 ppm or less; or 30 ppm or less; or 15 ppm or less, based on the weight of the solution.

  The method of the present application can be used for various purposes. An example of this purpose is as follows. Water systems such as cooling water systems, boilers, reverse osmosis units, evaporators, pools, washers, oil recovery processes, etc. are subject to scale formation and corrosion on internal surfaces. Addition of a dispersant polymer (eg, a polymer or copolymer of the carboxylic acid described above) helps in reducing scale formation or corrosion, or both. The concentration of such polymers or copolymers in aqueous systems is known to change over time, and it is therefore desirable to provide a method for analyzing the concentration of such polymers in aqueous systems.

  One way to analyze the concentration of such polymers in aqueous systems is to use the aforementioned polymer or copolymer carboxylic acid having a detectable end as the dispersant polymer. It is also envisaged to use a blend of one or more polymers or copolymers of carboxylic acids without detectable ends and one or more polymers or copolymers of carboxylic acids with detectable ends as dispersants.

  In some embodiments where a dispersant polymer is added to the aqueous system, other materials can be added to the aqueous system. Such other materials include, for example, one or more of phosphates, zinc, azoles, phosphonates, biocides, other useful materials, and combinations thereof.

Test Method In the following examples, the scanner used was an IRISCard ^™ Pro scanner from IRIS. This is a self-feeding business card scanner with 238 dots per centimeter (600 dots per inch) resolution, 24-bit color, and adjustable scan range of 11.8 cm x 30.5 cm (4.25 inches x 12 inches) It is.

  The test strip was 0.64 cm x 6.4 cm (0.25 inch x 2.5 inch). The card was 5.1 cm x 8.9 cm (2 inches x 3.5 inches) and gray.

Strategic Diagnostics, Inc. Analyte solutions were analyzed using an OPTIDOSE ^™ TestKit available from: According to the instructions in the test kit, 50 microliters of the sample solution was added to the test tube, and then the supplied buffer solution was added to the line labeled “5 ppm”. 100 microliters of the resulting mixture was transferred to a reagent vial and the test strip was placed in the vial. After 10 minutes, the test strip was removed and allowed to dry for 15 minutes. The strip was then taped to a gray card. Scanning the gray card and excluding 10 pixels with the weakest red intensity in each identified rectangle from the process of summing the green values of all pixels in the rectangle (after color reversal) And the image was analyzed as described above to obtain a ratio R.

Example 1
OPTIDOSE ^(trademark) 1000
Various solutions were prepared and tested using the test procedure described above. Each solution was OPTIDOSE ^™ 1000 in deionized water. The results are as follows and show the concentration (Conc.) (Ppm) and the color intensity ratio R.

The linear least squares best fit for these data was CA = 10.188 x R-2.6557 (R square value is 0.9888).

Example 2
OPTIDOSE 2000
The procedure of Example 1 was used except that the specimen was OPTIDOSE ^™ 2000.

The linear least squares best fit for these data was CA = 10.742 × R−2.067 (R square value is 0.9829).

Example 3
OPTIDOSE ^™ 3100
The procedure of Example 1 was used except that the specimen was OPTIDOSE ^™ 3100.

The linear least squares best fit for these data was CA = 11.7 × R−0.9399 (R square value is 0.977).

Example 4
Reproducibility test When various reproducibility tests were performed, the reproducibility of the test was excellent. For example, a replication solution was prepared using OPTIDOSE ^™ 2000. On each day, one solution was prepared and scanned 10 times. The procedure was repeated for 4 days. A total of 37 scans were performed. The solution had 9.5 ppm OPTIDOSE ^™ 2000. Overall, for all measurements, the average ratio R was 9.7 and the standard deviation was 0.48.

Claims (7)

A method of identifying the intensity of the red line color on a white test strip, comprising:
(A) attaching the white test strip to a card that is larger and darker than the white test strip (B) scanning the card with the attached white test strip;
(C) creating a digital image of the card, wherein each pixel in the digital image has a red value, a green value, and a blue value;
(D) using said digital image, viewed including the steps of calculating the intensity of color for each red line on said white test strip,
The step (D)
(A) identifying a first red line and identifying a first rectangle corresponding to the first red line;
Here, the first rectangle is
(I) is approximately or exactly centered on the test strip in the horizontal direction;
(Ii) smaller than the test strip in the horizontal direction;
(Iii) extends vertically above the first red line in the vertical direction;
(B) identifying a second red line and identifying a second rectangle corresponding to the second red line;
Here, the second rectangle is
(I) is approximately or exactly centered on the test strip in the horizontal direction;
(Ii) smaller than the test strip in the horizontal direction;
(Iii) extends vertically above the second red line in the vertical direction;
(C) optionally repeating step (b) for each additional red line to identify additional rectangles corresponding to said additional red line;
(D) perform color inversion calculations, and
(E) After performing steps (a), (b), (c), and (d), calculate the sum of the green values of all pixels in each rectangle to correspond to the first rectangle Performed using a method that includes generating a first sum of green values, a second sum of green values corresponding to the second rectangle, and optionally a further sum of green values corresponding to each additional rectangle, Method. Said second sum of Green values, further comprising the step of calculating the ratio of said first sum of Green values, the method of claim 1.   A chromatographic process in which one end of the pre-test strip is placed in a solution results in the test strip, the solution comprising an analyte and a complexing agent capable of forming a complex with the analyte, the pre-test strip comprising the A reference assay substance line that can turn red when contacted with a free molecule of a complexing agent, and a line of test assay substance that can turn red when contacted with a molecule of the complex of the analyte and the complexing agent. Item 2. The method according to Item 1. The method of claim 3 , wherein the analyte is a polymer. The method of claim 4 , wherein the polymer is a dispersant polymer. 6. The method of claim 5 , wherein the dispersant polymer has one or more detectable ends selected from a chain transfer agent, an initiator or fragment thereof, and a group attached to the chain transfer agent. The pre-test strip contains one or more printed images, each printed image being a known distance from each of the lines of reference assay material and from the line of test assay material. Item 4. The method according to Item 3 .